JP3172970B2 - ATM network bandwidth allocation method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ATM (Asynchronous Tras) suitable for transferring information such as data, images, and sound.
The present invention relates to an nsfer mode (asynchronous transfer mode) network and, more particularly, to an ATM network bandwidth allocation method suitable for efficiently performing various communications such as multi-connection and multi-point communication.

[0002]

2. Description of the Related Art Broadband ISDN (Integrated Services Digital Telecommunication Network; Inte ...
grated Services Digital Network) uses, for example, the ATM technology described on pages 168 to 177 of "Nikkei Communication Separate Volume ISDN Utilization Guide" (published by Nikkei BP, 1988). This AT
In M, the use of cells, which are fixed-length blocks, makes it possible to provide a comprehensive communication network independent of the type of communication service.

The ATM network has terminals and exchanges, and transmission links connecting the terminals and exchanges. The transmission link is logically divided into virtual paths (VPs). In this VP, a virtual channel connection (VCC: Virtua) is established between the calling terminal and the called terminal at the time of call setup.
l Channel Connection) is set. In the cell header of each cell, information for specifying a VP (VPI: Virtual Path)
Identifier) and information for specifying the VCC in the VP (VC
I: Virtual Channel Identifier)), and the exchange can identify which VCC carries information corresponding to each cell by the VPI and VCI.

The exchange has a cell header conversion table (also referred to as a mapping table) for determining a cell transfer destination.
And a switch for performing cell exchange processing, and a VPI
And a processor for performing signal processing for determining / VCI, setting a cell header conversion table, and reserving a band. During communication, VPI / VCI determination between terminals, setting of a cell header conversion table on an exchange, and communication between terminals are performed. Make a bandwidth reservation.

[0005] This bandwidth reservation is described in, for example, "Introduction to ATM: Passport to the Multimedia Era" (1994, Yokogawa Digital Computer Corporation SI Business Division).
This is necessary to avoid congestion, as described on page 62 of Toppan Inc., Japan. For example,
With respect to the transfer capacity of 150 Mb / s, the transfer capacity corresponding to the amount of incoming cells is secured in advance so that the amount of cells flowing in does not exceed it.

As described above, in the ATM network, "VP
I / VCI determination "," cell header conversion table setting ",
By performing "bandwidth reservation", communication between terminals is performed. When communicating between general unspecified subscribers,
These processes are performed for each communication, and at the end of each communication, “band release”, “cell header conversion table release”, and “VPI / VCI release” are performed.

FIG. 3 shows a configuration example of an ATM network. In this figure, 1 to 3 are terminals (described as T in the figure), 4 and 5 are exchanges (described as EX in the figure), 6 to 13 are VPs, 14 to 19
Is VCC. The terminal 1 sets VCCs 18 and 19, which are one-way communication paths, with the terminal 2 via the exchange 4. VCC18 is a terminal 2 in VP8.
By having a communication capacity (band) between the exchange 4 and the terminal 4 and having a band between the switch 4 and the terminal 1 in the VP 7, information can be transferred from the terminal 2 to the terminal 1. Then, in the configuration of FIG. 3, in order to enable two-way communication, VCC is used.
18 and VCC 19 are set between the terminals 1 and 2.

[0008] VCC is a VC link (VCL) defined between a terminal and a switch, a switch and a switch, and a switch and a terminal.
Cascade connection. For example, for VCC18, one VCL exists between the terminal 2 and the exchange 4, one VCL exists between the exchange 4 and the terminal 1, and for the VCC 17, the terminal 1
One VCL is provided between the exchanges 4, between the exchanges 4 and 5, and between the exchange 5 and the terminals 3.

In such an ATM network, various communication modes such as multi-connection communication and multi-point communication can be realized. For example, in multi-connection communication,
By providing a plurality of VCCs in one direction for one call, it is possible to transfer information for each medium such as voice and image. In the multipoint communication, communication with a plurality of destinations can be performed by one call. For example, when performing multipoint (two-way) communication between the terminals 1 to 3, VCCs 14 to 19 may be set for one call.

Further, when the same information is provided to a plurality of destinations, a multipoint VCC 20 having a plurality of destinations can be set as shown in FIG. However, in this case, the exchange 4 needs a cell copy function. In the current communication procedure, after a VCC is set between the terminal 1 and the terminal 3 (or the terminal 2), the terminal 2 (or the terminal 3)
To add multiple destination VCCs (multipoint VCC2
0).

When a TV conference (multipoint communication) is being performed between the terminals 1 to 3 in FIG. 3, the information to be transferred is the voice information and the image information of the speaker who is the caller. When the speaker is the terminal 1, the VCCs 17 and 19 need a sufficient band, but the other VCCs (VCC 14
No band is required for １６16, 18). Similarly, when the speaker is at the terminal 2, sufficient bandwidth is required for the VCCs 16 and 18, and when the speaker is at the terminal 3, the
4 and 15 need a sufficient band. As described above, the VCC requiring a band fluctuates every moment.

In the conventional ATM function, since a band is assigned to each VCC, an equivalent band is assigned to each VCC with each terminal as a speaker. Therefore, when multipoint communication is performed between the terminals 1 to 3 in FIG. 3, it is necessary to secure a band (W) for each of the VCCs 14 to 19. As a result, each of the terminals 1 and 4, the switches 4 and 5, the switches 5 and 3, and the switches 4 and 2 can be sufficiently handled in a band of (1 × W). Despite this, a band of (4 × W) is secured.

[0013]

The problem to be solved is that, in the prior art, multi-point communication or multi-connection communication in which a plurality of virtual channel connections (VCC) are set for one call is actually performed. In this case, it is not possible to secure only a necessary and sufficient band. An object of the present invention is to solve these problems of the prior art,
An object of the present invention is to provide a band allocation method for an ATM network that enables effective use of a band in multipoint communication, multiconnection communication, and the like.

[0014]

In order to achieve the above object, the present invention provides a method for allocating a bandwidth to an ATM network, comprising the steps of: (1) providing a plurality of virtual channel connections for one call such as multipoint communication and multiconnection communication; (VCC)
In setting up a call in an ATM network, a band shared by a predetermined combination of VCCs constituting the call is reserved, and the reserved shared band is assigned to each VCC of the same combination by each actual VCC. Is assigned under predetermined assignment conditions in accordance with the communication status of (2) In the bandwidth allocation method of the ATM network described in (1) above, a predetermined combination and a predetermined allocation condition set by a user are notified from a calling terminal at the time of setting a call, and each VCC constituting the call is notified. The set exchange is characterized in that, if there is a VCC that satisfies the combination condition, a shared band is allocated to each VCC based on a predetermined allocation condition, and the allocated band is captured. (3) In the band allocation method for an ATM network according to any one of the above (1) and (2), the allocation of the shared band
And performed for each virtual channel link (VCL) accommodated in the same virtual path (VP).
(4) In the bandwidth allocation method for an ATM network according to any one of the above (1) to (3), the combination condition and the allocation condition are based on the number of VCCs constituting the call and the shared bandwidth for each VCC. , And at least the number of pieces of the specific assignment information. (5) In the bandwidth allocation method for an ATM network according to any one of the above (1) to (3), the combination condition and the allocation condition are determined by multiplying the number of originating terminals by multipoint communication.
It is characterized by including at least the sum of the number of called terminals, information indicating a specific method of allocating the shared band, and the number of the specific allocation information. (6) In the bandwidth allocation method for an ATM network according to the above (4) or (5),
The specific allocation information of the shared band is characterized by including at least the weight given to each VCC and the value of the reserved band.

[0015]

According to the present invention, a plurality of Vs for a single call, such as multipoint communication and multiconnection communication.
When setting the CC, the band (W) is shared by the VCCs of the same set. That is, as in the prior art, each V
Instead of reserving a band (W) for each CC, a band (shared band (W)) is reserved for each combination of VCCs. Then, the reserved shared band (W) is allocated to each VCC according to the actual communication condition. For example, in multipoint communication, a band is required only for VCC from one information source, and that information source moves. In such a case, the shared band (W)
Is assigned to the VCC over which cells from the moved information source are transmitted. In particular, the called terminal can communicate on the called subscriber line in the same band as when one information source is fixed.

As described above, according to the present invention, in a multipoint communication with another n points, when the information source moves from one of these n points every moment, one information source is placed on the called subscriber line. Can be communicated in the same band as when there is a fixed number, and can be realized in 1 / n the band of the prior art. In this way, communication can be realized without capturing the required maximum bandwidth of each VCC, and in particular, the bandwidth of the called subscriber line can be effectively used. Also, in the multi-connection communication, even when the required bandwidth for a call is constant, but the required bandwidth at each VCC changes, by applying the present invention, it is possible to respond by capturing only the required bandwidth, The bandwidth can be used effectively. Note that a VP link (VP
By notifying L) to the network, the present embodiment can be easily extended to a VP service that provides a necessary and sufficient band to the VP network of the user.

[0017]

Embodiments of the present invention will be described below in detail with reference to the drawings. 1 and 2 are flowcharts showing an example of an operation procedure according to the present invention of the ATM band allocating method of the present invention,
FIG. 3 is a block diagram showing a first configuration example of an ATM network for performing the operation procedure. The ATM network shown in FIG. 3 includes a terminal (denoted by T in the figure) 1 as described in the section of the prior art.
~ 3, and exchanges (described as EX in the figure) 4,5,
VPs 6 to 13 are set between the terminals 1 to 3 and the exchanges 4 and 5, VCCs 14 to 19 are set between the terminals 1 to 3, and V
For CC18, between terminal 2 and exchange 4 and exchange 4
-Each terminal 1 has one VCL, and VCC17
, Between the terminal 1 and the exchange 4, the exchange 4 and the exchange 5
And between the exchange 5 and the terminal 3 are each one VCL.
It is.

An operation according to the present invention when a TV conference (multipoint communication) is performed between the terminals 1 to 3 in the ATM network having such a configuration will be described. First, as shown in FIG. 5, a call setting operation is performed between the terminals 1 to 3 and the exchanges 4 and 5. That is, the call setting for the terminals 2 and 3 notified from the terminal 1 to the exchange 4 is notified from the exchange 4 to the exchanges 5 and 2, and the terminal 3 is notified from the exchange 5. The ACK (response acknowledgment message) from the terminal 2 that has received the notification is returned to the terminal 1 via the exchange 4, and the ACK from the terminal 3 is returned to the terminal 1 via the exchange 5 and the section unit 4.

At the time of this call setting notification, in this embodiment, the terminal 1 notifies the exchange 4 of a VCL capable of sharing the band. As explained in the prior art section,
In the multipoint communication, when a speaker who is a sender of voice information and image information moves between the terminals 1 to 3, a VCC requiring a band fluctuates every moment. In the conventional ATM function, a band is assigned to each VCC, and an equivalent band is assigned to each VCC with each terminal as a speaker, and a band equal to or more than a necessary and sufficient band is captured.

In this embodiment, for example, VP10
For the VCLs belonging to the VCCs 16 and 17 in the VP 12 (between the exchange 4 and the exchange 5) and the VP 12 (between the exchange 5 and the terminal 3), it is sufficient to provide the bandwidth for one speaker. The VCL that can be shared is notified from the terminals 1 to 3 to the exchanges 4 and 5 at the time of call setting, so that a necessary and sufficient band is given to each call. By allocating the band in this way, efficient use of the band is possible.

Hereinafter, the operation will be described. First, terminal 1
At the time of call setup, in addition to the attributes (the destination and the band W) of each VCC constituting the call, the band condition between the VCCs is indicated by a signal link (not shown in the figure for simplicity). To the exchange 4. Here, the band condition is a condition that the band W only needs to be given to the VCC from the speaker. In particular, when paying attention to the destination terminal, the band sharing condition, that is, the relationship between the bands of each VCC is shown. W (16) + W (17) = W (the bandwidth W is shared by the VCCs 16 and 17) W (14) + W (19) = W (the bandwidth W is shared by the VCCs 14 and 19) W (15) + W (18) = W (the bandwidth W is shared by the VCCs 15 and 18) is notified.

Actually, (i) VCC "16", "1"
Since a number such as "7" cannot be used, the coordination number of the VCC forming the call (for example, coordination numbers 1 to 6 respectively correspond to VCCs 14 to 19) is used, and (ii) the form of the conditional expression is Since a value obtained by multiplying a band of each VCC forming a call by a certain weight has a certain value, a weight vector in which the weights are arranged in the order of coordination numbers and the value are transmitted as a signal. Will be.

As a result, the above-mentioned conditions include an information element “There are three conditions” and (0,0,1,1,0,0), W (1,0,0,0,0,1). ), W (0,1,0,0,1,0), W. As shown in FIG. 6, such conditions include "coordination number" indicating the number of VCCs, "condition number" indicating how many conditions exist, and "n-th condition subfield" indicating the content of each condition. Is notified in the configuration of the “bandwidth condition information field” having

On the basis of this condition, the exchange 4
It is determined whether or not the band of each VCC can be captured within .about.11. That is, in this example, each VCC requires a band W, but depending on the band conditions, it is replaced with whether or not the band W ′ can be captured. For example, since the band condition has been notified,
When a band can be assigned to the VCC 16, it is understood that the band of the VCC 17 may be "0" (that is, "W '= 0").

Therefore, the exchange 4 determines whether or not the VCC 17 can capture the band “0”. For other VCCs, “W ′ = W”. Then, when the bandwidth can be acquired for each VCC, a call setting notification is notified to the terminal 2 and the exchange 5 by a signal link. If the call cannot be caught, it is regarded as a call loss. The terminal 2 that has received the notification returns an ACK for the call setup to the exchange 4, and the exchange 4 returns an ACK to the terminal 1.

On the other hand, the exchange 5 that has received the notification
When the call setting notification is received from VPs 12 and 13,
It is determined whether or not the bands of CCs 14 to 17 can be captured. At this time, referring to the band condition again, if the band of VCC16 can be captured in VP12, the band of VCC17 may be "0" in VP12 (W '= 0). For other VCCs, “W ′ = W”. Each VCC
If the band can be captured, a call setting notification is transmitted to the terminal 3 which is the destination terminal via the signal link, and if not, it is determined as a call loss.

The terminal 3 that has received the notification sets A to the call setup.
The CK is returned to the exchange 5, and the exchange 5 returns an ACK to the exchange 4, and the exchange 4 returns an ACK to the terminal 1, which is the calling terminal. In this way, after the VCC is established between the terminals 1 to 3, the user information is sent in the cell. In this case, the application operates so that the band is given only to the speaker. For example, in the ATM layer, a cell may be transmitted to each terminal as in the related art.

Hereinafter, such operation will be described in detail with reference to FIG.
This will be described with reference to FIG. In FIG. 1, when a call setting notification is transmitted from an originating terminal (for example, terminal 1 in FIG. 3) to an originating exchange (for example, exchange 4 in FIG. 3) (step 10).
1) The calling exchange captures a band based on the shared band condition included in the call setting notification. That is, first, the band W of the incoming VP of the VCC of the coordination number 1 is captured, and if it can be normally captured (step 10).
2), the band W of the outgoing VP of the VCC with the coordination number 1 is captured (step 103), and the operation proceeds to the operation of capturing the VCC with the next coordination number (2) (step 105). Step 102 and step 10
In 3, if the band W cannot be captured, a call loss is determined (step 104).

Next coordination number (i = 2)
Does not exceed the number of coordinations set as the band condition (step 106), based on the band condition, the input VP of the VCC of the coordination number (i).
(Step 107), and the input V
The band W 'of the coordination number (i) of P is captured (step 108). Thereafter, the required band W 'of the outgoing VP of the VCC of the coordination number (i) is reviewed based on the band condition (step 109), and the band W' of the coordination number 2 of the outgoing VP is captured (step 110). When the acquisition of the band is completed, “i =
i + 1 "as the next coordination number (i =
The process proceeds to 3) acquisition of the band (step 112). Incidentally, in step 108 and step 110, the band W '
If the call cannot be captured, the call is determined to be a call loss (step 111).

This operation is referred to as "i> number of coordinations ".
, Ie, if the acquisition of the band for all the target VCCs has been completed normally (step 10
6), a call setting notification is made to the destination terminal (for example, terminal 2 in FIG. 3) or the exchange (for example, exchange 5 in FIG. 3) (step 113). When the call setting notification is sent to the destination terminal in this way (step 114), the destination terminal transmits the call
CK is returned (step 115), and the originating exchange transmits an ACK to the originating terminal (step 116).

On the other hand, as shown in FIG. 2, in the destination exchange notified of the call setting from the calling terminal (step 200),
First, the VP band W of the destination terminal side (for example, the terminal 3 in FIG. 3) of the VCC with the coordination number 1 is captured (step 201), and then the capture operation of the VCC with the next coordination number (i = 2) is performed. Move on (Step 2
02). When the coordination number (i) exceeds the number of coordinations set as the band condition,
If not (step 203), the necessary band W 'of the destination VP of the VCC of the coordination number (i) is reviewed based on the band condition (step 204), and the required band W' of the coordination number (i) of the incoming VP is checked. Capture is performed (step 205). Then, when the acquisition of the band is completed, "i = i + 1" is set, and the process proceeds to acquisition of the band of the next coordination number (i = 3) (step 20).
6). In step 205, if the band W 'cannot be captured, a call loss is determined (step 207).

This operation is called "i> number of coordinations".
(That is, if the acquisition of the bands for all the target VCCs is completed normally (step 20)
3) A call setting notification is sent to the connection destination terminal (step 208). When the called switch notifies the called terminal of the call setting, the called terminal returns an ACK to the called switch (step 209), and the called switch returns to the calling switch (step 210). (Step 211). After the VCC is established between the terminals 1 to 3 in this way, the transfer of the user information is started (step 212).

The present invention in multipoint communication has been described above. Next, an embodiment of the present invention in multiconnection communication with the configuration shown in FIG. 7 will be described.
FIG. 7 is a block diagram showing a second configuration example of the ATM network for performing the operation procedure of the ATM band allocating method in FIG. In the second embodiment, in the form shown in FIG.
And the terminal 22 are communicating with each other.
Are the audio channels of the band "W1", and VCC32 and 34 are the image channels of the band "W2". When the image information is to be refined, the audio channel band is lowered to "W1 '" and the image channel information is changed to "W2". Consider the situation of raising to "".

In this case, the bandwidth sharing condition is “W = max
(W1 + W2, W1 ′ + W2 ′), W (31) + W (32) = W (bandwidth W is shared by VCC 31, 32) W (33) + W (34) = W (VCC 33, 34) And share the band W). That is, in the format shown in FIG. 6, “coordination number = 4”, “condition number = 2”, “first condition subfield = 1100 W”, and “second condition subfield = 0011 W” are set, and the bandwidth is determined by the procedure in FIG. I just want to capture.

Next, a third embodiment of the present invention having the configuration shown in FIG. 8 will be described. FIG. 8 is a block diagram showing a third configuration example of the ATM network for performing the operation procedure of the ATM band allocating method in FIG. In the third embodiment, communication is performed between the terminals 41 and 42 and between the terminals 41 and 43 in the form shown in FIG. The terminal 41 distributes data to the terminal 42 at a time determined by the center function, and also distributes data to the terminal 43 in the meantime. Note that distribution from the terminal 41 to the terminal 42 and the terminal 43 is not performed at the same time.

The VCCs 51 and 52 are composed of a terminal 41 and a terminal 42.
This is a channel for data distribution control signals between
Transmits the data itself on the same channel. The bands are “W” and “W ′”, respectively. Similarly, VCC 53, 54
Are the VCC (band W) for the data / data distribution control signal between the terminal 41 and the terminal 43 and the VCC for the data distribution control signal.
(Band W ′). In this case, the band sharing condition is: W (51) + W (53) = W (bandwidth W is shared by VCCs 51 and 53) W (52) + W (54) = W '(VCCs 52 and 54) The bandwidth W ′ is shared), and using this, the bandwidth is captured for each of the receiving terminals 42 and 43 in the procedure shown in FIG.

As described above with reference to FIGS. 1 to 8, in the ATM band allocating method according to the present embodiment, the VCL capable of sharing the band is notified to the network at the time of call setting.
Necessary and sufficient bandwidth can be given to each call. As a result, the required bandwidth for a call is constant in multi-connection communication, but when the required bandwidth in each VC changes, or in a multipoint communication, a bandwidth is required for a connection from an information source. For example, when a user moves, communication can be realized by capturing only the required bandwidth without capturing the required maximum bandwidth of each connection, and the bandwidth can be effectively used. In particular, the bandwidth of the destination subscriber line can be used effectively. For example, even when multipoint communication is performed with other n points and the information source moves from one of these n points every moment, the same bandwidth as when one information source is fixed is present on the called subscriber line. , And can be realized with 1 / n the bandwidth of the conventional technology.

The present invention is not limited to the embodiment described with reference to FIGS. 1 to 8, and can be variously modified without departing from the gist thereof . Also , when providing a VP between a plurality of user network interfaces (UNIs), the VPs within the same transmission path (virtual container)
By notifying the condition about sharing of the band for C,
It can be easily inferred that an efficient bandwidth allocation method for VPC can be implemented.

[0039]

According to the present invention, the bandwidth to be assigned to each VCC can be changed every moment as needed, the bandwidth can be used effectively, and the communication efficiency in multi-connection communication, multi-point communication, etc. is improved. Let economical A
TM service can be provided.

[Brief description of the drawings]

FIG. 1 is a flowchart showing the first half of an operation procedure example according to the present invention of the ATM band allocating method of the present invention.

FIG. 2 is a flowchart showing the latter half of an operation procedure example according to the present invention of the ATM band allocating method of the present invention.

FIG. 3 is a block diagram showing a first configuration example of an ATM network for performing an operation procedure of the ATM band allocating method in FIG. 1;

4 is a multipoint VC in the ATM network in FIG.
It is explanatory drawing which shows the example of the setting state of C.

FIG. 5 is a sequence diagram showing an example of a call setting operation in the ATM network in FIG. 3;

FIG. 6 is an explanatory diagram showing a format example of a shared band condition according to the present invention.

FIG. 7 is a block diagram showing a second configuration example of an ATM network for performing an operation procedure of the ATM band allocating method in FIG. 1;

FIG. 8 is a block diagram showing a third configuration example of the ATM network for performing the operation procedure of the ATM band allocating method in FIG. 1;

[Explanation of symbols]

1-3: terminal, 4, 5: exchange, 6-13: VP, 14
To 19: VCC, 21, 22: terminal, 23, 24: exchange, 25 to 30: VP, 31 to 34: VCC, 41 to 4
3: terminal, 44: exchange, 45 to 50: VP, 51 to 5
4: VCC.

Claims (6)

(57) [Claims] 1. In an ATM network for setting up a plurality of virtual channel connections (VCC) for one call, such as multipoint communication and multiconnection communication, at the time of setting up the call, each of the VCCs constituting the call is set up. Of the shared band is reserved in the predetermined combination, and the reserved shared band is assigned to each VCC of the same combination by each actual VC.
A bandwidth allocation method for an ATM network, wherein allocation is performed under predetermined allocation conditions in accordance with the communication status in C. 2. The ATM network bandwidth allocation method according to claim 1, wherein the predetermined combination and a predetermined allocation condition set by a user are notified from a calling terminal at the time of setting the call, and the call is configured. When there is a VCC that satisfies the combination condition, the exchange that has set each VCC assigns the shared band to each VCC based on the predetermined assignment condition, and captures the assigned band. ATM network bandwidth allocation method. 3. The bandwidth allocation method for an ATM network according to claim 1, wherein the allocation of the shared band is accommodated in the same virtual path (VP) which constitutes each of the VCCs. Each virtual channel link (VCL)
A bandwidth allocation method for an ATM network, which is performed in units. 4. The bandwidth allocation method for an ATM network according to claim 1, wherein the combination condition and the allocation condition are the number of VCCs constituting the call and the specific number of the shared band. A bandwidth allocation method for an ATM network, comprising at least information indicating a proper allocation method and the number of the specific allocation information. 5. The band allocation method for an ATM network according to claim 1, wherein the combination condition and the allocation condition constitute a call in multipoint communication.
A bandwidth allocation method for an ATM network, comprising at least the number of VCCs, information indicating a specific allocation method of the shared band, and the number of the specific allocation information. 6. The bandwidth allocation method for an ATM network according to claim 4, wherein the specific allocation information of the shared band includes a weight assigned to each VCC, and A bandwidth allocation method for an ATM network, comprising at least a value of a reserved bandwidth.